The present invention relates to methods and apparatus for locating various entities, including human beings and animals, by observing and detecting a force and subsequent resulting torque, acceleration, vibration or other measurable, quantifiable manifestation of the force created by the non-uniform three-dimensional electric field spatial gradient pattern exhibited uniquely by an entity and being detected by the device of the present invention as used by the device""s human operator.
The detection of visually obscured entities has many uses in fire-fighting, search and rescue operations, law enforcement operations, military operations, etc. While prior art devices are known that detect humans, animals and other materials, some by measuring changes in an electrostatic field, none of the operable prior art devices uses the force resulting from the non-uniform electric field squared spatial gradient three-dimensional pattern exhibited uniquely by an entity to indicate the precise location and line-of-bearing direction of the subject entity relative to the device""s human operator.
By using an electrokinetic effect, dielectrophoresis, which induces a force and subsequent resulting torque on an antenna and other component parts of the device, the present invention gives a rapid line-of-bearing directional location indication of the subject entity. A meter can also be provided to indicate the direction of strongest non-uniform electric field squared spatial gradient signal strength for those situations where the dielectrophoretic force and subsequent resulting torque, acceleration, vibration or any other measurable quantifiable manifestation of the force is extremely small and difficult to detect.
It should be noted that while the present invention works for many different types of entities, a primary use of the present invention is to locate animate entities and, in particular, human beings, irrespective of the presence or absence of obscuring material structures (walls, trees, earthen mounds, etc.), of rfi and emi interference signals, of adverse weather conditions, and of day or night visibility conditions.
The nature and source of an animate entity""s (in particular human) electric field and its spatial gradient being detected in the dielectrophoresis effect generating the directionally self-correcting force and subsequent torque characteristic of an animate entity, line-of-bearing locator device has been discussed in Bioelectromagnetism, R. Plonsey et al. (eds.), Oxford University Press (1995) and R. A. Rhoades, Human Physiology, Harcourt Brace Javanioch (1992). The empirical evidence in the case of humans is quite persuasive that human heart electro-physiology generates by far the strongest electric field and spatial gradient pattern. In human physiology, the central and peripheral nervous system neurons, the sensory system cells, the skeletal muscular system, the independent cardiac conduction cells, and the cardiac muscle system cells operate via polarization and depolarization phenomena occurring across all respective cellular membranes. The electric potentials associated with these polarization fluctuations are routinely used at a human body surface for empirical correlation/clinical diagnostic purposes, such as the ECG for the heart and the EEG for the brain. The heart has by far (about a factor of 70 compared to the brain) the largest voltage, electric field and electric field spatial gradient pattern in the human body compared to the other operating systems mentioned above.
The human heart is a special case wherein the conduction SA node, the VA node, Purkinje fibers, etc. provide high polarization (95 mV) and very rapid (ms) depolarization (110 mV) potentials. The dipole electric field fluctuations are periodic and frequent. The carrier frequency of de- and re-polarizations occurs in a range of 72 for adults to 120 in babies (beats per min. or 1.2 to 2.0 Hz). The frequency spectra of ECG patterns have main lobes at about 17 Hz. In sub-ULF (0 to 3 Hz) and ULF (3 to 30 Hz) frequency ranges, the electric and magnetic fields are quasi-static and are not strongly coupled asxe2x80x9cEM waves,xe2x80x9d and EM activities detected in these ranges have a predominantly magnetic or electric nature (heart electric field is many times larger than heart magnetic field, see Bioelectromagnetism, R. Plonsey et al., Oxford University Press (1995)) as discussed in D. O. Carpenter, Biological Effects of EM Fields, Academic Press (1994). Normal neuron or cardiac activity aberrations, such as strokes/heart attacks, create a temporary or permanent depolarization resulting in loss of polarization and an inability to repolarize. The heart""s resultant polarization electric field distribution pattern has a high degree of spatial non-uniformity and can be characterized as a moving dipolar charge distribution pattern during each heartbeat. The human heart electric field pattern is unique and is thus able to be detected.
Traditionally, inanimate dielectrics have been found to exhibit three main and one rare polarization modes (electronic, atomic, orientation and the rare nomadic) as discussed in Properties of Polymers, D. W. van Krevelen, Elsevier Publ. (1976); A. R. von Hippel, Dielectrics and Waves, John Wiley and Sons (1954); Dielectric Materials and Applications, A. R. von Hippel (ed) John Wiley (1954); H. A. Pohl, Dielectrophoresis, Cambridge University Press (1978). These modes lead addivtively in the sequence given as one goes from UHF (1018 Hz) to ULF (3 to 30 Hz) to sub-ULF (0 to 3 Hz) dielectric constraints of 1.0 for air to 78 for water with essentially all plastics in a 3 (PVC) to 14 (Bakelite) range. There are rare outriders like the solvent NMMA at 191, Se at 1xc3x97103and ferroelectric BaTiO3 and rare nomadic polymers (CS2)xc3x97at 2xc3x97104 and PAQR carbazole at 3 xc3x97105.
Mammalian physiology results for the ULF dielectric constants of mammalian (human) living tissues, wherein mammalian (human) tissues are 70% volume water (dielectric constant 78), show that all the ordinary animate human tissues, like heart, brain, liver, heart, blood, skin, lung and even bone, have quite extraordinarily high ULF dielectric constants (105 to 107), found only very rarely in usual inanimate dielectric materials. See Biomedical Engineering Handbook, J. D. Bronzino (ed.), CRC Press (1995); Physical Properties of Tissue, F. A. Duck, Academic Press (1990); H. P. Schwan, Advances in Biological and Medical Physics, 5, 148 to 206 (1957); E. Grant, Dielectric Behaviour of Biological Molecules, Oxford Univ. (1978) and Handbook of Biological Effects of Electromagnetic Fields, 2nd Ed., C. Polk et al., CRC Press (1996). It is also found that as the animate tissues die these extraordinarily high ULF dielectric constants collapse downward greatly to more normal inanimate values over time as the dying tissue becomes, over time, inanimate. The reason for the great differences is the routine occurrence of other polarization modes in animate materials, but which occur very rarely in inanimate materials. These other polarization modes are interfacial (inhomogeneous materials) and pre-polarized elements which occur readily in all animate tissues. It is known that the rest state of the human neural, cardiac, skeletal muscular and sensory systems are states of high polarization and are induced via ion (K+, Na+, Ca++, etc.) transport across various membranes. Action potentials from this transport are used to maintain the systems"" normal polarized state and to trigger the systems"" activities via depolarization and follow-up rapid repolarization signals.
Dielectrophoresis has been practiced mostly using exclusively artificially-set-up external non-uniform electric field patterns in laboratories to dielectrically separate individual (xcexcm size) inanimate, inorganic particles or xcexcm size living cells (see, H. A. Pohl, Dielectrophoresis, Cambridge University Press (1978) and H. A. Pohl, Electrostatics and Applications, Chapters 14 and 15, A. D. Moore (Editor), Interscience Press (1973) and T. B. Jones, Electromechanics of Particles, Cambridge University Press (1995)). The problems of this prior art in trying to observe the dielectrophoresis force and torque effects in meter-size ensembles of tens of billions of xcexc-size vertebrate cells coupled biochemically and working in concert as an animate entity are overcome by utilizing naturally-occurring electric field spatial gradient patterns, in particular the largest electric field spatial gradient pattern occurring in vertebrates, the one associated with vertebrate""s beating heart, illustrated by the electrocardiogram (ECG). Table I lists the electro-physiology events in human heart beat cycles forming ECG""s. A vertebrate is any animal having a backbone and some form of heart (one or more chambers) with a characteristic ECG.
FIG. 1 shows a human heart including right atrium 11, right ventricle 12, left atrium 13 and left ventricle 14. FIG. 2 shows the dipolar voltage and electric field patterns of the human heart. Curves (a) 21 and (b) 22 are the positive and negative isopotential lines. The curves (c) 23 are the resulting non-uniform electric field lines. FIG. 3 shows cardiac muscle or conduction cell membrane 31, through which various ions 32 (sodium and potassium) diffuse to form the polarized membrane resting state 33 and the depolarized activated state 34, the states being electrically linked and characterized by the action potential curve 35. FIG. 4 shows electro-physiology of the human heart. Sequential action potential curves are superimposed from the heart key action centersxe2x80x94sinus node 41, atrial muscle 42, A-V node 43, common bundle 44, bundle branches 45, Purkinje fibers 46, and ventricular muscle 47xe2x80x94to produce ajoint waveform 48 called an electrocardiogram (ECG). FIG. 5 shows a detailed normal ECG with characteristic waveform featuresxe2x80x94P 51, P-R interval 52, P-R segment 53, QRS spike 54, QRS interval 55, S-T segment 56, S-T interval 57, T 58, U 59 and the Q-T interval 50. FIG. 6 shows the moving depolarization vector at key electrical events in the 600 ms human cardiac heartbeat cyclexe2x80x94atrial depolarization at 80 ms 61, septal depolarization at 220 ms 62, apical depolarization at 230 ms 63, left ventricular depolarization at 240 ms 64, late ventricular depolarization at 250 ms 65, ventricles depolarized at 350 ms 66, ventricular repolarization at 450 ms 67, ventricles repolarized at 600 ms 68. The QRS spike waveform feature in the ECG is by far the largest electric field and has the greatest spatial gradient (across the left ventricular membrane wall).
The present invention detects the presence of various entities using an electrokinetic effect known as dielectrophoresis. As discussed above, a primary use of the present invention is detecting and locating animate entities such as human beings that are obscured from sight. The electrokinetic effect used by the present invention, dielectrophoresis, is one of five known electrokinetic effects, (the other four being electrophoresis, electro-osmosis, Dorn effect, and streaming potential), and describes the forces affecting the mechanical behavior of initially neutral matter that is dielectrically polarized by induction via spatially non-uniform electric fields. The spatial non-uniformity of an electric field can be measured by the spatial gradient of the electric field.
The dielectrophoresis force depends non-linearly upon several factors, including the dielectric polarizibility of the surrounding medium (air plus any intervening walls, trees, etc.), the dielectric polarizibility and geometry of the initially neutral matter (the device""s antenna and other component parts of the device), and the spatial gradient of the square of the human target""s local electric field distribution as detected at the device""s antenna and other component parts. The dielectrophoresis force is produced by the spatial gradient of the target""s field, which induces a polarization charge pattern on the device""s antenna and other component parts, and this force is a constant direction seeking force always pointing (or trying to point) the device""s antenna and other component parts toward the maximum in the three-dimensional non-uniform electric field squared spatial gradient pattern uniquely exhibited by a predetermined entity type.
This constant-direction-seeking force is highly variable in magnitude as a function of the angular position and radial position of the entity-to-be-located (like a human target) with respect to the device""s antenna and other component parts of the device, and upon the effective dielectric polarizibilities of the intervening medium (like air) and of the materials used in the device""s antenna and other component parts. The following equations define the dielectrophoresis forces wherein Equation 1 shows the force for spherical initially neutral objects (spherical antenna and the device""s other component parts), and Equation 2 shows the force for cylindrical initially neutral objects (cylindrical antenna and the device""s other component parts).
F=2(xcfx80a3)∈0K1 (K2xe2x88x92K1)/(K2+2K1)∇|E0|2xe2x80x83xe2x80x83Equation 1
xe2x80x83F=L/a(xcfx80a3)∈0K1(K2xe2x88x92K1)/(K2+K1)∇|E0|2xe2x80x83xe2x80x83Equation 2
Where:
F is the dielectrophoresis force vector detected by the antenna and the device""s other component parts;
a is the radius of the sphere or cylinder;
L is the length of the cylinder (L/a is the so-called axial ratio);
∈0 is the permittivity constant of free space;
K2 is the dielectric constant of the material in the sphere or cylinder;
K1 is the dielectric constant of fluid or gas, (air) surrounding both the entity and the antenna and the device""s other component parts;
E0 is the electric field produced by the entity as detected by the antenna and the device""s other component parts; and
∇ is the spatial gradient mathematical operator.
The human-operated, hand-held locator device produces an observable torque as the antenna/locator detector device swings around the hand-held pivot point and acquires a local electric field spatial gradient max which gives via the dielectrophoresis force, a pinpoint line-of-bearing location of the human target. The detector specifiously locates the human heart""s asymmetrical position in the human thoraic cavity, which is just left of the human target""s sternum if the human target is front-facing the human operator and just right of the human target""s sternum if the human target is back-facing the human operator. The size and extent of the observable torque depends on the angular, radial and vertical planar positions of the human operator. Despite human target movements, the antenna-locator detector is self-correcting, it reacquires in real time and locks-on to the spatial gradient signal and again pinpoints the living human target""s heart. At sub-ULF and ULF frequencies utilized in the human heart electro-physiology, attenuation skin depths are extraordinarily large, so the detector can sense or detect through metals, earth, walls and all other vision-obstructing barriers.
The dielectrophoresis-based human heart line-of-bearing locators utilize living humans in two distinct roles as both target and operator for these devices. As to the living human""s role as target, the ECG voltages and fields at the human body""s thoraic cavity surface produced by the beating human heart were found first to mimic an average electric dipole distribution. More detailed ECG data led to an explanation via a more complex depolarization and repolarization vector moving in a ULF reproducible spatial sequence pattern throughout the heart""s four chambers and other structures during a heart beat. This moving polarization vector (see FIG. 6) is the electric field and spatial gradient thereof that the line-of-bearing locator locks onto and real time tracks using the dielectrophoresis effect. See Bioelectromagnetism, R. Plonsey et al. (eds.), Oxford University Press (1995) and R. A. Rhoades, Human Physiology, Harcourt Brace Jovanioch (1992).
The electric field patterns and gradients generated by the heart""s electric dipole would be expected to fall off rapidly with distance as the inverse square or cube of distance. But the human field patterns sensed by the line-of-bearing human locator between the human operator and the human target empirically behave as if they emanated from phase- and amplitude-coupled, partially (mostly)-coherent, partially-constructive interference ULF electric field generator producing an almost-distance-independent, highly-amplified electric field gradient pattern which interacts with the antenna/locator detection device via the dielectrophoresis effect to produce the force and observed torque even out to as far as 500 meters. This effect is not unlike the difference between a random thermonic emission light bulb (incoherent, phase- and amplitude-uncoupled, modest intensity, very distance-dependent light source) and an amplified stimulated emission laser light source (coherent, phase- and amplitude-coupled, very high intensity, almost distance-independent light source). Hence, the detection/locator system is able to xe2x80x9ctune-inxe2x80x9d to human signals even at very large distances.
The low-impedance connection between the universal ground (earth) and the two very high dielectric constant (semiconductive) human entities are believed to form some type of ULF resonant cavity type oscillator system. An analogy can be drawn with UHF microwave tuned-to-be-absorbed-by-water Klystron-like oscillators used in microwave ovens to cook food. Independent experimental evidence is available and growing to partially support this viewpoint on the almost-distance-independent effects seen with this invention""s line-of-bearing dielectrophoresis force and torque human locator device. See Biological Coherence and Response to External Stimuli, H. Frohlich, Springer-Verlag Press (1988); Coherent Excitations in Biological Systems, H. Frohlich, Springer-Verlag Press (1983); Electromagnetic Bio-Information, F. Popp, et al., Urban Publ. (1979); W. Tiller et al. Cardiac Energy Exchange Between People, HeartMatch (1997); and W. Tiller, Science and Human Transformation, Pavior, Walnut Creek (1997).
It should be noted that the term xe2x80x9cantennaxe2x80x9d as used in this context includes, (in a very real sense), all of the components and the living human operator present in the device of the present invention. To this extent, the dielectric constant of the materials including living biological tissue (human operator) that make up the locator of the present invention all determine the overall value of K2 in the above equations. These materials are not arranged in a uniform spherical or cylindrical shape, and therefore the exact value of K2 and the exact functional relationship of K1 and K2 in a closed mathematical equation form accurately representing the real world locator device is difficult, if not impossible, to determine. In a practical sense, experimentation has shown (and is continuing to show) the types and placement of dielectric materials needed to produce maximum dielectrophoretic force and subsequent resulting torque, acceleration, vibration or any other measurable quantifiable manifestations of the force for precisely locating different types of entities. The following table lists some of the dielectric materials used in the locator (K2 values) and/or surrounding (such as air, water, walls, etc.) the locator (K1 values) and the dielectric constant for these materials.
The above discussion and equations concerning dielectrophoresis provide a rational explanation of the operating principles of the present invention that is consistent with all empirical observations associated with the present invention. These operating principles involve using the above mentioned forces to point an antenna and all other components attached to the device toward the maximum gradient of the local electric field, to thereby indicate the line-of-bearing direction toward an unseen entity.
In accordance with the invention, an operator holds the locator device in hand, and through a handle, the locator device is electrically and dielectrically connected to the operator. The operator is partially electrically grounded (through the operator""s feet), and thereby the individual human operator body""s capacitance (C) and resistance (R) to true ground are connected electrically to the handle of the locator device. Ranges for an individual entire human body""s C have been measured as 100 pF to 400 pF and for individual human body""s R have been measured as 0.03 Kxcexa9 to 1 Mxcexa9. Thus, the generalized electrical parameter (the polarization charge pattern induced on the device by the electric field spatial gradient of the entity in this case, but also electric field, current and voltage) exponential decay time (=RC) constant range for the variety of human being bodies potentially acting as locator device operators is about 3 to 400 xcexc seconds. This decay time constant is greatly increased through an externally connected resistor of up to 5000 Mxcexa9 and inductor with an inductance up to 200 mH or a capacitor with a capacitance up to 56 mF, which results in an effective human operator""s exponential decay time constant up to 1 to 10 seconds.
This enables dielectrophoretic forces caused by the induced polarization charges (bound, not free) pattern on the locator device""s antenna and other component parts to be detected, replenished instantly with each new heartbeat and locked onto since the force is replenished faster than the induced polarization charge pattern on the device can decay away to true ground through the operator""s body. This effect is called, and is using, the spatially self-correcting nature of the dielectrophoretic force (always pointing or trying to point to the maximum of an entity""s electric field three-dimensional squared spatial gradient pattern).
The locator device is held in a balanced (two to three degrees tilt angle down from absolute) horizontal state, and the operator scans the locator device in a constant speed uniform linear motion back and forth. An antenna extends from the front of the locator device and is acted on by the aforementioned force. This force creates a subsequent resulting torque around a well defined pivot line, which is constant-direction-seeking and tends to make the locator device""s antenna and the device""s other component parts point toward the maximum spatial gradient of the square of the non-uniform electric field uniquely exhibited by any target human beings or other predetermined animate entity within the range of the locator device.
The effect creates a self-correcting action of the locator device when the human operator scans the device in a uniform motion to lock onto a target entity initially. The effect also creates an additional self-correcting action of the locator device to closely follow the radial and angular motions of an entity (to track and reacquire a target entity once the operator has initially locked onto a target entity). The self-correcting action of the locator device to reacquire a target occurs without any additional overt action on the part of the human operator, and the device thereby is operating independently of the human operator.
Four internal N-channel J-FETs (field effect transistors) are connected to the locator device""s antenna and operate in their non-linear range to effectively change the antenna""s length. Three of these FETs are arranged in modules that are equidistant from the antenna""s longitudinal axis and are spaced 120 degrees apart. The fourth FET is arranged in a module below the axis and to the rear of the locator device. Three potentiometers are provided on the first three modules to adjust the current levels through the first three FETs and thereby tune the locator to point directly at a human being""s body located at a precise known position as a reference target entity. The gain and frequency response of the fourth FET by virtue of the voltage pattern induced by the reference entity is adjusted by a six position switch connected to the base of an NPN transistor. By changing the frequency response of the locator device, the device is tuned to reject the higher frequency electromagnetic signals and noise from all external sources, including those sources associated with the human operator in order for the locator device to interact with and respond to only the three-dimensional non-uniform electric field squared spatial gradient pattern exhibited uniquely by a predetermined entity type.
While scanning the locator device in a constant uniform motion back and forth in front of a known entity (such as a human, if the target is a human being), the operator changes the six position switch until a maximum force and subsequent resulting torque is detected and used to aim the antenna and the device""s other component parts toward the target entity. After selecting the setting of the six position switch, the operator adjusts the gain of the first three FETs until the locator device points or tries to point directly at the target entity. For different entities, different dielectric materials are used in the locator device""s antenna and its other component parts. Examples of detectable entities include human beings, other mammals as well as other biological entities such as birds, reptiles, amphibians and other vertebrae. Continued research on the instrument has yielded positive results in the instrument""s ability to be tailored both as a geometrical design and with respect to materials and other components of construction to specifically detect a variety of different target entities.
Accordingly, it is an objective of the invention to provide an accurate method of locating the direction and position of a target animate entity relative to the instrument""s human operator. It is another objective of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.